Bulk fill delivery venturi system

ABSTRACT

A particulate distribution system for transporting seed or other particulate from a source into a plurality of metering bins, the system including a forced air source, a converter for splitting air form the source into separate flows in converter outlet lines, venturis for receiving the air flows and entraining particulate from a main hopper therein and a manifold delivery system that directs the entrained particulates to mini-hoppers and that opens at an outlet end back into the main hopper.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

FIELD OF THE INVENTION

[0003] The present invention is related generally to agriculturalimplements and more specifically to an improved apparatus and method fortransferring agricultural seed or other particulate material from aprincipal storage site to individual material metering hoppers mountedon planters, grain drills and the like.

BACKGROUND OF THE INVENTION

[0004] In the past, distribution of seed (or other particulate materialsuch as fertilizer) for use in a variety of agricultural operations hasbeen facilitated via a planter apparatus including a wheel supportedcarrier frame having a hitch for linking to a tractor or other primemover, an implement bar mounted to the frame perpendicular to thetransport direction and a plurality of row units (e.g., 8 to 32) mountedto and essentially equi-spaced along the length of the implement bar.Among other components, each row unit typically includes some type ofseed bin that opens downwardly into a dispenser assembly and some typeof soil agitator (e.g., a coulter or knife member) juxtaposed on thetransport side of the dispenser. During transport through a field theagitator is forced through soil there below and forms a seed trench. Asits label implies, the dispenser dispenses a pre-selected quantity ofseed downward and behind the agitator into the trench.

[0005] The individual seed bins generally have limited storage capacity.For instance, many row unit seed bins are limited to between one andthree bushel volumes. For this reason, these types of planter assembliesrequired frequent bin refilling. Unfortunately, seed filling stations(e.g., typically a barn or other storage unit) are typically stationaryand therefore filling exercises often required a trip out of the fieldsback to a station and then a trip back to the fields to continue theseeding process. These filling trips increased the overall time requiredto plant fields. In addition to the round trip time required to refillbins, the refilling process itself was tedious as each separate row unitbin had to be filled during each filling exercise.

[0006] In an effort to reduce the number of seed refilling exercisesrequired to seed a field, the industry has developed systems includingone or more large seed reservoir hoppers mounted to the carrier framethat are transported along with the row units. A seed distributionsystem in which seed is conveyed from an equipment-mounted main hopperis described in U.S. Pat. No. 5,161,473 (hereinafter the '473 patent)which issued on Nov. 10, 1992 and which is assigned to Deere andCompany. The '473 patent utilizes a single main hopper which dispensesseed to a plurality of individual mini-hoppers that each, in turn,supply seed to an individual row unit. The seed is fed from the mainhopper into each mini-hopper by entraining it in an air stream containedin separate, individual seed transfer hoses that are connected betweenthe main tank and each of the individual mini-hoppers. To minimizecosts, ideally, the mini-hoppers are designed to be as small as possibleand to require as little material as possible.

[0007] U.S. Pat. No. 5,379,706 (hereinafter “the '706 patent”) whichissued on Jan. 10, 1995 and is assigned to Agco Corporation describesanother seed transporting system which also utilizes a central storagehopper for supplying a plurality of smaller satellite hoppers via aplurality of individual hoses or tubes running from the central hopperto each of the individual row units. Thus, while the systems of the '173and '706 patents provide for the maintenance of seed supply quantitiesin the row hoppers or bins during seeding operations, they also requirethe incorporation of a large number of separate seed transport tubes inthose systems where multiple, mini-hoppers are present. As in the caseof most mechanical systems, in the case of multiple mini hopper systemsrequiring separate feed tubes, costs associated with the additional seeddelivery tubes and related components are appreciable.

[0008] To reduce seed delivery costs associated with multi-tube deliverysystems, there have been attempts at configuring a delivery systemincluding essentially a single seed delivery tube or manifold assemblyfor delivering seed to all or an appreciable number (e.g., half) of therow units. For example, U.S. Pat. No. 6,047,652 (hereinafter “the '652patent”) which issued on Apr. 11, 2000 and which is assigned to the sameassignee as the present invention, teaches a delivery system having amanifold assembly including a plurality of manifold sections anddiverting structures that together form a single sinuous-shapedpassageway that opens into each of four separate metering bins. Aseparate diverter structure is mounted generally above each of themetering bins. A supply duct is linked between the particulate sourceand the first diverting structure and a separate intermediate duct ismounted between each two adjacent diverting structures.

[0009] The source described in the '652 patent includes a fan at thebase of a main hopper that blows air through a head of seed and into abottom end of the supply duct. Exemplary supply and intermediate ductsmay be approximately 2 inches in diameter. Each diverting structure, asits label implies, diverts a portion of the air borne seed entering thestructure downward through a tube and into an associated metering bin.Another portion of the seed entering each diverting structure isdirected to a following manifold duct and hence to a subsequentdiverting structure and corresponding metering bin.

[0010] The '652 patent embodiment includes four separate manifoldconfigurations fed by a single fan source where each manifold feeds fourseparate metering bins. Other configurations are contemplated. Forinstance, where the fan is powerful enough 6 or even 8 metering bins maybe fed via a single manifold configuration.

[0011] According to the '652 patent, the structure described operates asfollows. With seed or some other particulate in a main hopper, when theair source is turned on, seed is entrained in the air and forced throughthe manifold assembly. As seed passes through the diverting structuressome of the particulate is diverted into each of the metering bins.Eventually the bins fill with seed and the diverting structures becomeblocked. When one diverting structure becomes blocked, the air borneseed is delivered to other unblocked structures and, theoretically,there is a constant seed source provided to instantly refill themetering bins.

[0012] In reality, unfortunately, it has been found through empiricalevidence that the '652 patent assembly has at least two importantshortcomings. First, when all of the diverter structures become blocked,particulate and air flow to the manifold assembly as a whole is blocked.When the manifold as a whole is blocked the seed in the manifoldgenerally settles and is not air borne. Thereafter, when one or more ofthe diverter structures becomes unblocked via metered seed distribution,there is a delay period during which the manifold flow resumes when noseed is delivered to the unblocked structure. Where the metering binsare relatively small, the delay periods have been known to result themetering bins being emptied prior to manifold seed delivery. This isparticularly true in the case of the row units that are farthest removedfrom the source. Even short periods of empty bins causes unevendistribution of seed material which is unacceptable in manyapplications.

[0013] Second, the air-seed source configuration used to deliver seed inthe '652 patent, it turns out, is not very efficient. To this end,generally, it has been determined that seeds can be transportedsatisfactorily with an air velocity of 5000 to 6000 feet per minute(FPM). With a 2 inch hose diameter, 5000 to 6000 FPM velocity translatesinto approximately 150 cubic feet per minute (CFM) of air.

[0014] An exemplary fan employed in delivery experiments was designed torun at peak efficiency (approximately 48%) when it deliversapproximately 1000 to 2000 CFM of air at a speed between 3450 and 6000RPM.

[0015] Unfortunately, experiments have shown that, with the exemplaryfan employed in the '652 patent air-source configuration, theconfiguration was able to deliver seeds from a main hopper to 6 to 8metering bins when the fan was running at around 5500 and 6000 RPM. Inother words, with the '652 patent configuration, instead of generating2000 CFM of air at 6000 RPM, the fan running at 6000 RPM only generatedapproximately 140 CFM of air at the ends of the manifold duct and thusfan efficiency was less than 10%. This air volume loss is attributablein great part to imperfectly sealing duct and diverter connectors, thesinuous or curved configuration of the manifold and the pressurerequired to, in effect, blow through the head of seed that fills thebottom end of the main hopper.

[0016] Moreover, in the case of larger planter assemblies including morerow units, for example, 32 row units, the fan employed in theexperiments would not be able to deliver sufficient air pressure to meetdelivery requirements.

[0017] One solution to the air pressure problem may be to employ apositive displacement blower instead of a fan to overcome all of thepressure losses in the manifold. Positive displacement blowers are wellknown in the pneumatics art and therefore will not be described here indetail. Unfortunately, while a positive displacement blower may overcomemay be more efficient at providing required air pressure throughout aline, such blowers are relatively expensive and therefore are costprohibitive in most applications.

[0018] Therefore, a need exists for a single manifold particulatedelivery system that will not cause delay periods during which air borneparticulate flow must be re-established. In addition, it would beadvantageous to have a fan or air source configuration that isrelatively inexpensive and yet extremely efficient.

BRIEF SUMMARY OF THE INVENTION

[0019] It has been recognized that a venturi can be mounted between afan and the supply duct of a manifold configuration with a mainparticulate hopper opening down wind of a restricted portion (i.e., theventuri orifice) of the venturi so that fan air supplied to the venturicreates a negative pressure at the orifice sufficient to drawparticulate into the air stream and deliver the particulate to themanifold. As in the case of the '652 patent, the venturi feeds aplurality of series connected metering bins to supply seed thereto. Byusing a venturi to draw seed into an air flow instead of requiring thefan to blow through a head of seed, an appreciably more efficientconfiguration is provided where the initial air pressure drop throughthe seed head is eliminated.

[0020] In one embodiment, the fan feeds a converter assembly that splitsthat fan air into a plurality of separate air streams in separate airhoses and each of the separate hoses feeds a separate venture which inturn feeds a plurality of series connected metering bins. In aparticularly useful embodiment, the number of converter outlet hoses isselected by taking into account fan efficiency parameters and the CFMrequired through each of the venturi connected manifolds to efficientlydeliver seed to the metering bins. To this end, as indicated above, theexemplary fan is most efficient when delivering between 1000 and 2000CFM at speeds between 3450 and 6000 RPM and, for proper seed deliverythrough a 2 inch tube, approximately 140 CFM of air is required. Thus,where the converter includes eight separate outlet tubes, the combinedCFM required for eight outlet tubes is 1120 CFM the fan runs within itspeak efficiency range of 1000 to 2000 CFM. Other configurations withinthe peak range are contemplates.

[0021] After the number of converter outlets has been determined, thenumber of metering bins to be fed by each venturi can be determined bydividing the total number of row units required by the number ofconverter outlets. For example, where 32 row units are required and theconverter has eight outlets, the number of row units fed by each outlet,venturi and manifold configuration is four. It should also be noted thatwhere only four units are fed by each venturi the pressure drop throughthe manifold linked to the venturi will be less than where more unitsare fed and thus efficiency is enhanced in this manner as well.

[0022] Unfortunately, as in the case of the '652 patent configuration,the venturi configuration described above can result in delay periodproblems when diverter structures become blocked. In addition, where themain hopper opens downward into the venturi, when diverter structuresbecome blocked, seed from the main hopper can fill a large portion ofthe venturi cavity and create a seed head. In this case, where aconverter splits fan air into fractional CFM, the air pressure is oftentoo small to overcome the seed head or may require even a longer delayperiod to push through a seed head.

[0023] It has been recognized that the problems described above andrelated to delay periods during which air borne particulate flow must bere-established can be overcome by simply providing a return manifoldduct or the like between the last in a series of diverter structures andthe particulate hopper or air source. By providing a return passagewaythat remains unobstructed at all times, even when all of the diverterstructure openings into the metering bins become blocked, the air borneparticulate flow continues through the return passageway and isconstant. Thus, when one or more of the diverter structures re-opens,particulate within the flow is immediately present to fill the meteringbin there below.

[0024] In addition, it has been recognized that the venturi can bedesigned to minimize or essentially eliminate the possibility ofbuilding up a seed head when all of the diverter structure openingsbecome blocked. To this end, by having the hopper open into a side orthe underside of the venturi, the seed can be prevented from filling andblocking the cavity while still providing a seed source at thehopper-venturi opening that can be sucked and entrained into the flowingventuri air. Some embodiments include each of the venturi concepts aswell as the return duct concept described above.

[0025] Consistent with the above discussion, the present inventionincludes an apparatus for pneumatically transporting particulatematerial from a main hopper to at least a first mini-hopper sub-set, theapparatus comprising a forced air source having a fan outlet, a venturimounted generally below the main hopper, the venturi forming a venturipassageway between an air inlet and a venturi outlet, the passagewayincluding a restricted section between the inlet and the venturi outletsuch that, when air is forced there through, the restricted sectioncauses a vacuum at a vacuum point downstream of the restricted section,the venturi also forming a particulate inlet proximate the vacuum point,the particulate inlet linked to the hopper for receiving particulatethere from and the air inlet linked to the air source and at least onemanifold assembly that links the venturi outlet to the first mini-hoppersub-set.

[0026] In some embodiments the particulate inlet opens into thepassageway from above. In other embodiments the particulate inlet opensinto the passageway from below. In still other embodiments theparticulate inlet opens into a lateral side of the passageway.

[0027] In some applications the apparatus is for, in addition todelivering particulate to the first mini-hopper sub-set, deliveringparticulate to N−1 additional mini-hopper sub-sets, in addition to theat least one venturi and the at least one manifold assembly, theapparatus further including at least N−1 additional venturis and N−1additional manifold assemblies, the N−1 venturis mounted generally belowthe main hopper and having a design similar to that of the firstventuri, the N−1 venturi air inlets linked to the air source and the N−1venturi particulate inlets linked to the hopper for receivingparticulate there from, each of the N−1 manifold assemblies linking aseparate one of the N−1 venturi outlets to a separate one of the N−1mini-hopper sub-set.

[0028] Here, the apparatus may further include a converter linked to theair source via a single air duct and including N separate converteroutlet ducts, each outlet duct linked to a separate one of the Nventuris, the converter dividing the air flow received form the airsource approximately evenly among the N outlet ducts. More specifically,the mini-hoppers may include X mini-hoppers and each sub-set mayincludes X/N mini-hoppers. In a particular embodiment X is 32 and N is8.

[0029] In some embodiments the manifold assembly forms a manifoldpassageway linked at an inlet end to the venturi outlet and havingopenings along its length that open into the mini-hoppers in thesub-set. Here, the manifold passageway may be sinuous where the openingsare vertically lower than the manifold passageway sections therebetween. More specifically, the sub-set may include Y series linkedmini-hoppers and the manifold may include diverter structures for eachof the first Y−1 mini-hoppers in the sub-set and a plurality of manifoldducts including a supply duct and intermediate ducts, each diverterstructure having an inlet and first and second outlets, the supply ductlinking the venturi outlet to the inlet of a first diverter structure, aseparate intermediate duct linking the outlet of a preceding diverterstructure to the inlet of a following diverter structure for the secondthrough (Y−1)st diverter structures, an intermediate duct linking theoutlet of the (Y−1)st diverter structure to the Yth mini-hopper and thesecond outlets of each of the diverter structures opening into separateones of the mini-hoppers. The end of the manifold passageway may openinto the main hopper.

[0030] Moreover, the invention further includes an apparatus forpneumatically transporting particulate material from a main hopper to atleast N mini-hopper sub-sets, the apparatus comprising a forced airsource having a fan outlet, a converter operably linked to the airsource to receive forced air there from and to split the received airflow into N separate air flows through N separate converter outletlines, N venturis mounted generally below the main hopper, each venturiforming a venturi passageway between an air inlet and a venturi outlet,each passageway including a restricted section between the inlet and theventuri outlet such that, when air is forced there through, therestricted section causes a vacuum at a vacuum point downstream of therestricted section, each venturi also forming a particulate inletproximate the vacuum point, the particulate inlets linked to the hopperfor receiving particulate there from and each air inlet linked to aseparate one of the converter outlets and N manifold assemblies, eachmanifold assembly linking a separate one of the venturi outlets to aseparate one of the N mini-hopper sub-sets.

[0031] Again, here, each manifold assembly may form a manifoldpassageway linked at an inlet end to a corresponding venturi outlet andhaving openings along its length that open into the mini-hoppers in acorresponding sub-set and, wherein, the ends of the manifold passagewaysopen into the main hopper.

[0032] These and other objects, advantages and aspects of the inventionwill become apparent from the following description. In the description,reference is made to the accompanying drawings which form a part hereof,and in which there is shown a preferred embodiment of the invention.Such embodiment does not necessarily represent the full scope of theinvention and reference is made therefore, to the claims herein forinterpreting the scope of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0033]FIG. 1 is a schematic illustration showing how the materialtransporting apparatus of this invention is used in conjunction withagricultural equipment;

[0034]FIG. 2 is a schematic view showing the present apparatus designfor transporting material from a supply bin to separate distributionbins;

[0035]FIG. 3 is a is an enlarged sectional view of a flow diverter;

[0036]FIG. 4 is partial sectional view of a portion of the supply binshowing how material is directed into the transport system;

[0037]FIG. 5 is a side view, partially sectioned, illustrating thedisposition of the outlet of a material diverter means in a distributionbin;

[0038]FIG. 6 is a schematic diagram illustrating an inventiveconfiguration including venturis and a converter linked to a fan;

[0039]FIG. 7 is a horizontal cross-sectional view of the exemplaryventuri of FIG. 6;

[0040]FIG. 8 is similar to FIG. 7, albeit of another venturi embodimentwhere a hopper opens into a lateral side of the venturi; and

[0041]FIG. 9 is similar to FIG. 7 albeit of yet one other venturiembodiment where a hopper opens into the underside of the venturi.

DETAILED DESCRIPTION OF THE INVENTION

[0042] For a more complete understanding of the invention, reference ismade to the drawings and initially to FIG. 1, which shows the pneumaticseed transporting system of this invention as it would be used inconjunction with an agricultural planter or seeder. In FIG. 1, a planter10 may be connected to a tractor (not separately numbered) for transportthrough a field. The planter or seeder 10, is shown as having twocentral storage or reservoir hoppers 12 and a plurality of individualdistribution or row metering hoppers or metering bins 13 that receiveseed from the storage hoppers 12 by means of a distribution system ormanifold assembly indicated generally by the numeral 15. Generallyspeaking, central storage tanks 12 could have capacities ranging from 20to about 60 bushels while the individual row bins wouldcharacteristically range from about 1 to 3 bushels in capacity. Each ofthe row metering bins 13 will have an associated seed metering devicethat applies the seed to the soil in a manner well-known in the art.

[0043] Referring also to FIG. 2, assembly 15 includes, among othercomponents, a plurality of manifold sections 18, 25, 70, and divertingstructures 26 that together form a single sinuous-shaped passageway thatopens into each of the metering bins 13. A separate diverter structure26 is mounted generally above each of the metering bins 13. A supplyduct or supply tube 18 is linked between the particulate source (e.g.,12 and 16) and the first diverting structure. A separate intermediateduct (collectively identified by numeral 25, three shown in FIG. 2) ismounted between each two adjacent diverting structures 26. Eachdiverting structure 26, as its label implies, diverts a portion of theair borne particulate entering the structure downward and into anassociated metering bin 13. Another portion of the particulate enteringeach diverter structure 26 is directed to a following manifold duct andhence to a subsequent diverter structure and corresponding metering bin.

[0044] In addition, a return duct 70 is mounted to the last diverterstructure in a series of structures and, as its label implies, is linkedback to the source 12. Return duct 70, like the other manifold ducts,forms an arcuate or curved passageway for transporting air born seed.Each seed supply duct 18 is connected to supply seed up to fourindividual row hoppers such that, in FIG. 1, the planting system iscapable of sowing seed in thirty-two rows with eight separate ducts 18.The delivery system includes a source of air, such as blower 16, that isconnected by air supply tubes 17 to the bottom of storage hoppers 12.Air entering hopper 12 picks up seeds and pneumatically transports themthrough tubes 18 into the inlet ends of first diverter structures 26, asshown in FIG. 4 and discussed below.

[0045] Referring still to FIG. 2, main manifold duct assembly 20 iscomprised of a series of manifold sections 25 that are joined at theinlet and outlet end of each section by seed flow diverting means 26.Sections 25 are configured in such a way that the midsection of is eachsection is located at an elevation that is further above the row bins 13than are the ends thereof so that the outlet end of each section extendsin a downward direction into the inlet 38 of a seed flow diverter 26 ofgenerally Y-shaped configuration. Diverter 26 has a downwardly directedoutlet 39 that can be used with a bin feed tube 28 which extends intothe interior of the bins for the flow of seeds there into and diverter26 has a second outlet opening 40 which extends upwardly for connectioninto the inlet side of the succeeding manifold section 25 (see. FIG. 3).Again, supply duct 18 and return duct 70 are linked to the inlet of thefirst diverter structure 26 and the outlet of the last diverterstructure 26, respectively, and each is also linked to the source 12,16.

[0046] As best seen in FIG. 3, an exemplary Y-shaped diverter 26 isshown connected to the outlet end 35 of a manifold section 25 and to theinlet end 36 of the following manifold section 25. The connection ofdiverter 26 to the outlet end 35 and inlet end 36 can be made withsuitable fasteners such as hose clamps 37. Thus, diverter 26 has aninlet opening 38, first outlet opening 35 and a second outlet opening40, as described above. As seed flows through the manifold section shownon the left in FIG. 3, it initially passes through the high point orupper node of the section 25 and then flows downwardly toward the outletend 35 and into the inlet opening 38 of diverter 26. The shape of thediverter directs seed flow straight down into the outlet opening 39 andinto bin feed tube 28. At the beginning of the bin filling operationvirtually all of the seed coming from a hopper 12 will flow into theinitial row bin, since the direction of seed flow in diverter 26 istowards opening 38.

[0047] Each of the manifold sections 25 is shaped in such a way that themid portion of the section located between the inlet and outlet ends islocated elevationally higher from the bins than are either the inlet orthe outlet end. That is, the overall configuration of the manifold ductforms a defined passage that is roughly sinuous so that the intermediateportion of each section 25 defines a relatively higher node and thediverting means 26 which connects the outlet end of one section to theinlet section of the following section defines a relatively lower nodein the passage. By providing an upwardly curved configuration in eachsection, material that is being advanced through the manifold 20approaches the diverter means 26, in each instance, in a downwarddirection so that it will be caused to continue to flow downwardly intoone of the underlying bins 13.

[0048] Diverter structure 26 may include a bin filler tube 28 whichextends downwardly into the associated bin and which may be adjustableto adjust how far the tube 28 extends into a corresponding the bin inorder that the quantity of seed accumulating in the bin can be varied.That is, more or less seed can be delivered into a bin depending uponthe quantity chosen by the operator to be sufficient in a particularapplication.

[0049]FIG. 5 of the drawings shows the manner in which bin filler tube28 can be located within the metering bin 13. Specifically tube 28extends adjustably into the bin through the top thereof, the particularlocation not being of any particular significance and the seed flowsinto the bin through the opening 50. After sufficient seed has enteredinto the bin, the orifice or outlet opening 50 will become blocked byseed and further entry of seed into that bin will continue until seedreaches diverter 26. By adjusting the position of opening 50 eitherhigher or lower within the bin 13, either greater or lesser quantitiesof stored grain can be held within each of the metering bins 13.

[0050]FIG. 4 of the drawings is an enlargement of the area encircled inFIG. 2 of the drawings, illustrating one means by which agriculturalseed can be entrained by air and entered into the inlet opening of thefirst arcuate section 25 of manifold 20. In this drawing duct 17 isconnected to the blower 16 (see FIG. 2) at one end and at the other endto the interior of hopper 12. The seed is held within the hopper 12above screen 55 which separates it from the air chamber 56 so that aircan blow upwardly and entrain the grain and cause it to flow out theduct 18 and on into the first manifold section 25. Seed above screen 55enters adjustable outlet tube 60 by means of the air flowing from blower16 and through the screen. The distance at which the lower end of tube60 is located with respect to screen 55 can be adjusted by the collarand nut arrangement 61 and the quantity of seed being entrained in theair varied proportionally.

[0051] In operation, the inlet end of supply section 18 is connected tosource 12. Source 12 may either be stationary or carried on the plantingapparatus, depending upon the user's preference. During the fillingoperation, the seed initially exits container 12 and flows upwardlythrough the upper node or high point of a section 18 and then downwardlythrough the outlet exit end of section 18 and through the first diverterstructure 26 into the first of the metering bins 13. After the first binhas become filled with grain and the grain has reached the bottom offirst diverter 26, the air flow within which the seed is entrained willbe carried outwardly through the other exit opening 40 of the firstdiverter 26 and into the inlet side of second section 25. Thereafter thefilling process that occurred with respect to the first metering bin isrepeated in the second metering bin until it is also filled. Theidentical operation will take place sequentially as each of the bins isfilled until the last of the bins in the series is filled.

[0052] Once all of the bins 13 are filled and corresponding structures26 are blocked, air entrained seed continues to flow through thediverter structures and manifold sections including return section 70back to the hopper 12. As grain is dispensed from the metering bins andan opening in the bottom of one of the diverter structures 26 is nolonger blocked by seed, air flow resumes and the bin is continuouslyrefilled with the pre-selected quantity of seed. Importantly, becausethe return duct 70 enables continuous seed flow, seed is immediatelyavailable to fill an unblocked diverter structure and maintain all ofthe bins filled.

[0053] Referring now to FIG. 6, a schematic diagram of a seed deliverysystem 69 including a plurality of venturis and a converter isillustrated. To this end, like the assembly described above, system 69includes a fan 16, a main hopper 12 and a plurality of metering bins ormini-hoppers 13 that are linked together by one or more manifoldassemblies (not separately illustrated in FIG. 6) where each manifoldassembly links four metering bins 13 in series. In addition, system 69includes a converter 74 and eight separate venturis 72 a through 72 h.

[0054] Converter 74 is linked to fan 16 via a relatively large duct 89(e.g., 5 inch diameter) and converts the air supplied via duct 89 intoseparate output air flows in eight separate output lines 76 (only oneconverter output line 76 numbered). Output lines 76 are relativelysmaller than duct 89 (e.g., lines 76 may be between 1½ and 2 inches indiameter.

[0055] Each of venturis 72 a through 72 h is generally identical andtherefore, in the interest of simplifying this explanation, only venturi72 a will be described here in detail. With respect to the otherventuris 72 b and 72 h, it should suffice to say here that each of thoseventuris is fed by a separate and distinct line 76 from converter 74 andeach in turn feeds a separate set of four series linked metering bins13. A return duct 70 links the last of each of the four series meteringbins 13 back into hopper 12. Thus, because there are eight venturis 72 athrough 72 h and each venturi feeds four separate bins 13, system 69 iscapable of delivering seed to 32 separate metering bins 13.

[0056] Referring now to FIG. 7, venturi 72 a includes three ports 80, 82and 84. Ports 80 and 82 are inlets and port 84 is an outlet. Inlet 80 isan air inlet, inlet 82 is a seed inlet and outlet 84 is a seed/airoutlet. Venturi 72 a is generally elongated and air inlet 80 and outlet84 are on opposite ends thereof. Venturi 72 a forms a passageway 100between inlet 80 and outlet 84. Passageway 100 has a relatively widediameter at inlet 80, narrows at a mid-section 86 and then expands againtoward outlet 84. Thus, as with most venturis, as air is forced throughrestricted section 86 along the direction indicated by arrow 90, the airvelocity increases and a vacuum is formed just to the right ofrestricted section 86 in FIG. 7.

[0057] Referring still to FIG. 7, seed inlet 82 opens downward intopassageway 100 at the point where restricted area 86 causes the vacuumto be formed (i.e., just to the right of section 86 in FIG. 7). Thus,seed at the bottom 88 of inlet 82 is sucked by the vacuum along thedirection indicated by arrow 91 into passageway 100 and is entrained inthe air so that seed and air moves along the direction indicated byarrow 92. The seed and air is directed out outlet 84.

[0058] Referring now to FIGS. 6 and 7, converter outlet line 76 islinked to venturi air inlet 80, seed inlet 82 is linked to an outlet onthe underside of hopper 12 and outlet 84 is linked to a manifoldassembly like the assemblies described above and thereby to four serieslinked metering bins 13.

[0059] In operation, as fan 16 and converter 74 force air into venturi72 a and through restricted section 86 via air inlet 80, the forced airgenerates a vacuum just below seed inlet 82 within passageway 100. Thevacuum draws seed into passageway 100 and the seed is entrained in theair and directed out outlet 84 to the linked metering bins. Return duct70 provides a path from the last diverter structure in the four binseries back to hopper 12.

[0060] Thus, it should be appreciated that system 69 overcomes the delayperiod problem due to blocked diverter structure openings by maintaininga constant conveyance of seed entrained air to fill the bins. Inaddition, system 69 overcomes the fan efficiency problem by adopting amulti-venturi design that allows the fan to operate relativelyefficiently to deliver seed to the large number of bins. To this end,again, where ideal manifold air volume is 140 CFM and efficient fanoperation calls for between 1000 and 2000 CFM, by configuring an eightventuri system, the fan can be operated in an efficient manner to createessentially ideal seed transport air flow rate (e.g., 8×140 CFM=1120 CFMwhich is between 1000 and 2000 CFM).

[0061] Referring now to FIG. 8, another embodiment 72 a′ of a venturi isillustrated. Venturi 72 a′ is similar to venturi 72 a except that,instead of opening upward to receive seeds from hopper 12 (see FIG. 6),seed inlet 82′ opens in a lateral side wall. In this case, it iscontemplated that, even in embodiments that do not include the returnduct 70, the venturi may be operable. To this end, it is believed thatwith the side wall opening, if all diverter structures become blocked,the entire passageway 100 will likely not blocked and therefore, when adiverter structure again becomes unblocked, the venturi will again beginto operate and deliver seed to the bins.

[0062] Referring now to FIG. 9, yet one other venturi embodiment 72 a″is illustrated. Venturi 72 a″ is similar to the venturi 72 a in FIG. 7except that seed inlet 82″ opens into the bottom side of venturi 72 a″and an inlet extension 102 wraps under venturi 72 a″ to feed seed from ahopper thereabove to inlet 82″. Thus, seed accumulates just below inlet82″ and, it is believed, will not enter passageway 100 unless the vacuumis generated thereabove. Thus, as in the case of embodiment 72 a′, hereit is believed that venturi 72 a″ will operate without return duct 70 todeliver seed.

[0063] It should be understood that the methods and apparatusesdescribed above are only exemplary and do not limit the scope of theinvention, and that various modifications could be made by those skilledin the art that would fall under the scope of the invention. Forexample, while a sinuous manifold assembly is described above thatincludes separate manifold sections and diverter structures, otherembodiments are contemplated that may include more than one of themanifold components as a single integral part. In addition, whiledescribed in the context of a seed delivery system, it should beappreciated that the present invention is applicable to other particletype delivery systems. Moreover, all of the concepts or sub-set of theconcepts described above may be combined to provide particularly usefulconfigurations. For example, any of the venturi designs (see FIGS. 7, 8,9) may be combined with a return duct 70. Furthermore, fewer or lesserventuris may be employed and/or fans with different operatingcharacteristics may be employed.

[0064] To apprise the public of the scope of this invention, thefollowing claims are made:

What is claimed is:
 1. An apparatus for pneumatically transportingparticulate material from a main hopper to at least a first mini-hoppersub-set, the apparatus comprising: a forced air source having a fanoutlet; a venturi mounted generally below the main hopper, the venturiforming a venturi passageway between an air inlet and a venturi outlet,the passageway including a restricted section between the inlet and theventuri outlet such that, when air is forced there through, therestricted section causes a vacuum at a vacuum point downstream of therestricted section, the venturi also forming a particulate inletproximate the vacuum point, the particulate inlet linked to the hopperfor receiving particulate there from and the air inlet linked to the airsource; and at least one manifold assembly that links the venturi outletto the first mini-hopper sub-set.
 2. The apparatus of claim 1 whereinthe particulate inlet opens into the passageway from above.
 3. Theapparatus of claim 1 wherein the particulate inlet opens into thepassageway from below.
 4. The apparatus of claim 1 wherein theparticulate inlet opens into a lateral side of the passageway.
 5. Theapparatus of claim 1 for, in addition to delivering particulate to thefirst mini-hopper sub-set, delivering particulate to N−1 additionalmini-hopper sub-sets, in addition to the at least one venturi and the atleast one manifold assembly, the apparatus further including at leastN−1 additional venturis and N−1 additional manifold assemblies, the N−1venturis mounted generally below the main hopper and having a designsimilar to that of the first venturi, the N−1 venturi air inlets linkedto the air source and the N−1 venturi particulate inlets linked to thehopper for receiving particulate there from, each of the N−1 manifoldassemblies linking a separate one of the N−1 venturi outlets to aseparate one of the N−1 mini-hopper sub-set.
 6. The apparatus of claim 5further including a converter linked to the air source via a single airduct and including N separate converter outlet ducts, each outlet ductlinked to a separate one of the N venturis, the converter dividing theair flow received form the air source approximately evenly among the Noutlet ducts.
 7. The apparatus of claim 6 wherein the mini-hoppersinclude X mini-hoppers and each sub-set includes X/N mini-hoppers. 8.The apparatus of claim 7 wherein X is 32 and N is
 8. 9. The apparatus ofclaim 6 wherein the particulate inlets open into the passageways fromabove.
 10. The apparatus of claim 6 wherein the particulate inlets openinto the passageways from below.
 11. The apparatus of claim 6 whereinthe particulate inlets open into lateral sides of the passageways. 12.The apparatus of claim 1 wherein the manifold assembly forms a manifoldpassageway linked at an inlet end to the venturi outlet and havingopenings along its length that open into the mini-hoppers in thesub-set.
 13. The apparatus of claim 12 wherein the manifold passagewayis sinuous where the openings are vertically lower than the manifoldpassageway sections there between.
 14. The apparatus of claim 12 whereinthe sub-set includes Y series linked mini-hoppers and the manifoldincludes diverter structures for each of the first Y−1 mini-hoppers inthe sub-set and a plurality of manifold ducts including a supply ductand intermediate ducts, each diverter structure having an inlet andfirst and second outlets, the supply duct linking the venturi outlet tothe inlet of a first diverter structure, a separate intermediate ductlinking the outlet of a preceding diverter structure to the inlet of afollowing diverter structure for the second through (Y−1)st diverterstructures, an intermediate duct linking the outlet of the (Y−1)stdiverter structure to the Yth mini-hopper and the second outlets of eachof the diverter structures opening into separate ones of themini-hoppers.
 15. The apparatus of claim 12 wherein the end of themanifold passageway opens into the main hopper.
 16. An apparatus forpneumatically transporting particulate material from a main hopper to atleast N mini-hopper sub-sets, the apparatus comprising: a forced airsource having a fan outlet; a converter operably linked to the airsource to receive forced air there from and to split the received airflow into N separate air flows through N separate converter outletlines; N venturis mounted generally below the main hopper, each venturiforming a venturi passageway between an air inlet and a venturi outlet,each passageway including a restricted section between the inlet and theventuri outlet such that, when air is forced there through, therestricted section causes a vacuum at a vacuum point downstream of therestricted section, each venturi also forming a particulate inletproximate the vacuum point, the particulate inlets linked to the hopperfor receiving particulate there from and each air inlet linked to aseparate one of the converter outlets; and N manifold assemblies, eachmanifold assembly linking a separate one of the venturi outlets to aseparate one of the N mini-hopper sub-sets.
 17. The apparatus of claim16 wherein the particulate inlets open into the passageways from above.18. The apparatus of claim 16 wherein the particulate inlets open intothe passageways from below.
 19. The apparatus of claim 16 wherein theparticulate inlets open into lateral sides of the passageways.
 20. Theapparatus of claim 16 wherein the mini-hoppers include X mini-hoppersand each sub-set includes X/N mini-hoppers.
 21. The apparatus of claim16 wherein each manifold assembly forms a manifold passageway linked atan inlet end to a corresponding venturi outlet and having openings alongits length that open into the mini-hoppers in a corresponding sub-setand, wherein, the ends of the manifold passageways open into the mainhopper.